1. Field
One embodiment of the invention relates to an optical disk apparatus which performs hash processing in response to presence/absence of an error of an optical disk and an optical disk processing method.
2. Description of the Related Art
As is well known, in recent years, many techniques for improving reproduction quality of an optical disk have become known according to advances in optical disks. As one of the techniques, there is an ECC circuit which detects an error of an optical disk to correct the same automatically.
Jpn. Pat. Appln. KOKAI Publication No. 10-334620 discloses a technique for enhancing detection ability to error correction caused by an ECC circuit without reducing capacity of user data of a recording apparatus to realize recording and reproducing processing of user data with high reliability.
In the technique described in JP-A-10-334620, however, error information detected by the ECC circuit is used for performing error correction. Accordingly, for example, how to leverage hash processing which is processing for corruption prevention in the Advanced Access Content System (AACS) processing is not known. The term “hash processing” described in this text means processing for confirming whether or not a certain stream unit (EVOBU) has been corrupted by calculating a hash value of the EVOBU to comparing the calculated result and an expected value with each other.